Electron tube with external anode



July 6, .1948. A. K. WING, JR 7 2,444,432 E ELECTRON TUBE W ITH EXTERNALANODE Filed March 14, 1946 VENTOR. ARTHUR KY wnve JR.

ATTORN Y Patented July c, 1948 2,444,482

ELECTRUN TUBE WITH EXTERNAL ANGDE Arthur K. Wing, 31a, Nutley, N. 3.,assignor to Federal Telephone and Radio Corporation, New York, N. 1 acorporation of Delaware Application March 14, 1946, Serial No. 654,270

3 Claims. ((31. 250-2l.5)

l 2 The present invention relates to electron tubes by an envelopeformed of a glass portion 4 and and more particularly to an electrontube having an anode portion 5. The anode portion 5 is an envelope, aportion of which is made of metal. flared and tapered to a knife edge 6where it is In such a tube the envelope may be an elec sealed to theglass envelope 4.. The external electrode of the tube such as an anode.For best 5 trode is grooved at l around the entire tube and results itis desirable that the distribution of just below the flared knife edgeportion 6. The

heat be uniform over the entire anode so that its groove '1 should bewide enough and deep enough entire surface will be effective in coolingthe elecso that it leaves a relatively long thin section 8 trode. In theprocess of evacuating the tube of the metal wall which acts as a thermalimthe external electrode is also heated. The best to p d n we the main yof the de d vacuum is obtained when the distribution of heat the seal.In the form disclosed the thickness of over the metal envelope isuniform and the entire the section 8 is less than half the anodethickwall is maintained at the proper exhaust temness. perature. Withsuch an arrangement heat is prevented Therefore an object of th presentinvention from flowing between the main body of the anode is to providean electron tube having a thick elecand the seal and the seal may beoled ndetrode as an external envelope of the tube over pe de t y y anySuitable external means w Which the distribution of heat will beuniform, out affecting the uniform distribution of heat in The externalelectrode which forms part of the the a cdch d SadVan cS that arise fromenvelope of the electron tube is sealed. to the glass using merely aseparate means for cooling the portion of the envelope of the tube. Ithas been electrode-to-glass seal are thus eliminated, By found that thisseal may be damaged by the using my invention it is possible to providea heat of the external electrode generated either thick Wall which willinsure uniform heat distriduring operation or during evacuation, and soit bution, while at the same time retaining ease of is desirable thatthe electrode at the location of r processing which will allow the bestdegree of the glass seal be kept at alower temperature than vacuum to beobtained. At the same time the that of the metal portion of theenvelope. Hereelectrode-to-glass seal is protected from overtcforeseparate means have been provided for heatin cooling the externalelectrode near the glass-to- I do not intend to limit the invention tothe metal seal, Such cooling means result in several preferredembodiment shown, except as may be detrimental features. In particularcooling eq e y the cl m Which wmeans has made a uniform distribution ofheat What I claim is: diiflcult. Moreover, the thicker the wall forgood 1. An electron tube comprising a glass portion heat conductivityand hence for uniform heat f ng t f e v p of said t a m a distributionthe more need there is for cooling. e t ode f g a othe Part of theenvelop Therefore a further object of my invention is U f d t e, a amctal-to-glass S al cto provide an electron tube with an externalelectween, said metal electrode being t pered to a trode so formed thatthe electrode-to-glass seal point in the re o of Said Seal. a delectrode may be maintained below a temperature at which e ng subject nts pe a g region to p the glass will soften and at the Same time the 40tures detrimental o id m 1 0-s1ass l, distribution of heat over theelectrode ma be and said electrode having an area of substantiallyuniform. reduced cross-section, said reduced cross-sec- A further objectof my invention is to provide t l ar a mpl y s p r t ng sa d p ti anelectron tube with an external electrode whose region from Said regionabout d Seal for thermal impedance is increased between the thickVenting t e flcW eat to d a electrode and the electrode-to-glass seal.An electron tube according 0 claim 1 in A more particular object of theinvention is t Which the cross-sectional area is reduced so thatincrease the thermal impedance by decreasing the e e p t is less t an fthe c o the thickness of the electrode at a region between Sectionalarea f the Test Of e electrode: the heated part of the externalelectrode and the An electron tube according o clalm 1 1n electrode-toglass Seal which the electrode is an anode of said tube.

Other objects and advantages of the present ARTHUR WING, invention willbe seen from the following description of a preferred physicalembodiment of REFERENCES CITED the invention and from the illustrationthereof'in The following references are of record in the theaccompanying drawing, in which the single fil of thi patent: figure is acentral longitudinal cross section of a portion of an electron tube withan external UNITED STATES PATENTS electrode forming part of theenvelope. Number Name Date In the figure a portion of an electron tubeI, 2,049,238 Weth et al. July 28, 1936 is shown with a cathode 2 andgrid 3 enclosed 2,173,906 Katsch o Sept. 26, 1939

